the u.s. government requires a person must be 21 to purchase a handgun from a licensed dealer, 18 years old to purchase a long gun, like a rifle, from a licensed dealer, but federal law does not regulate private sales between individuals or sales at gun shows or online. it's a state's right issue. the badi campaign for gun control rates five states atop of the scorecard for gun regulations with california at top of the list. >> we have universal background checks so you need a background check on any transfer of sale of a firearm, whether it's a gun dealer, gun show, private seller. >> reporter: laws that can be avoided in some cases simply by crossing state lines. the brady campaign's scorecard rates these states as having the weakest gun regulations. >> california, we might have good, strong gun laws but if you want to buy an assault weapon you drive across to nevada or arizona and you can buy them there easily without a background check and bring them across the border. we do need basic mea